In this paper, an analytical framework is presented to understand the generation of different intermodulation frequencies under dual excitation which is also verified with experiments. One single periodic frequency (SPF) excitation along with one variable frequency excitation, varying from local defect resonance (LDR) frequency and its superharmonics to subharmonic, are used. The flexural wave propagation in an orthotropic composite plate containing a delamination is analytically derived considering quadratic nonlinearity. Both analytical and experimental results are presented for glass fibre reinforced plastic (GFRP) plates with single and double delaminations. Two different types of intermodulation peaks are observed, that is local defect resonance intermodulation (LDRI) and single periodic frequency intermodulation (SPFI), out of which SPFI is found to be generated only during superharmonics and subharmonic excitation. At LDR frequency excitation, only its higher harmonics are found and no SPFI peaks are observed. The acoustic nonlinearity parameters are found increase with order of harmonics and delamination diameter.

中文翻译：

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使用双激励对不同互调频率的共振激活

在本文中，提出了一个分析框架来理解双激励下不同互调频率的产生，这也通过实验进行了验证。使用一种单周期频率 (SPF) 激励和一种可变频率激励，从局部缺陷共振 (LDR) 频率及其超谐波到次谐波。考虑二次非线性，分析推导出包含分层的正交各向异性复合板中的弯曲波传播。对具有单层和双层分层的玻璃纤维增​​强塑料 (GFRP) 板的分析和实验结果都给出了。观察到两种不同类型的互调峰，即局部缺陷谐振互调（LDRI）和单周期频率互调（SPFI），发现其中 SPFI 仅在超谐波和次谐波激励期间产生。在 LDR 频率激励下，只发现了它的高次谐波，没有观察到 SPFI 峰值。发现声学非线性参数随着谐波次数和分层直径的增加而增加。